Urwah bin al-Mughirah (may Allah have mercy on him) narrates from his father (Sayyiduna al-Mughirah bin Shu'bah, may Allah be pleased with him), and in it he said: I said: "O Messenger of Allah, shall I take off your leather socks?" He (peace and blessings be upon him) said: "I put them on while in a state of purity, and I have not become junub (in a state of major ritual impurity) since."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1337